目的 研究12名男性健康受试者单剂量口服国产与进口硝苯地平缓释胶囊(20 mg)后的人体内药物动力学和相对生物利用度。方法 12名男性健康受试者随机分为两组，进行双交叉自身对照试验。以尼莫地平为内标，用高分辨毛细管气相色谱-电子捕获(ECD Ni-63)检测法测定人血浆中硝苯地平的浓度。对血药浓度-时间数据以非房室模型依赖性方法估算药物动力学参数。结果 国产与进口制剂的 AUCo_～∞，c_max，t_max，t_1/2分别为(464.8±169.1)和(462.2±152.1)ng·h·ml^-1，(39.7±9.1)和(41.4±9.1)ng·ml^-1，(2.6±0.6)和(3.4±1.3)h，(10.4±4.0)和(10.1±4.4)h；经方差分析均无显著性差异(α=0.05)。国产缓释胶囊的相对生物利用度为(106.4±13.6)%。结论 国产与进口缓释胶囊生物等效，口服国产硝苯地平缓释胶囊20 mg可维持有效血药浓度达12 h。

OBJECTIVE The relative bioavailability between a China made and Ethypharm SA nifedipine oral sustained-release capsules (20 mg),and the pharmacokinetics were studied in 12 male Chinese healthy volunteers. METHODS The study was conducted in a two-treatment,two-period,two-sequence randomized cross-over trial.The plasma concentration of nifedipine after an oral single-dose in the subjects was determined with an electron-capture detecting high resolution capillary column gas chromatographic method with nimodipine as the internal standard and ether-0.2 mol·L^-1NaOH-cyclohexane (1.5∶1.0∶3.5 ml) as the extraction solvent.The important pharmacokinetic parameters were calculated with non-compartment method. RESULTS From the plasma concentration-time data of both preparations in the single-dose study,the AUC_0～∞,c_max,t_maxand t_1/2for China made and Ethypoharm SA nifedipine sustained-release capsules were (464.8±169.1) and (462.2±152.1) ng·h·ml^-1，(39.7±9.1) and (41.4±9.1) ng·ml^-1，(2.6±0.6) and (3.4±1.3) h,(10.4±4.0) and (10.1±4.4) h,respectively.And adequate ANOVA analyses showed that there were no significant difference (α=0.05) between them.The relative bioavailability of the sustained-release capsules was (101.0±12.2)%. CONCLUSION The China made nifedipine sustained-release capsules was able to maintain the plasma concentration above the effective level for about 12 hours after a single-dose.And there was no significant difference between the two preparations with two-one sided hypotheses at the α=0.05 level of significance.